Made a left inside 'upper' rail (12") and installed it. Tray straddles the INSIDE rails, not the outside ones screwed to the trunnion, since they're too wide for the tray guides

Started fitting the FT

Temporary AK recoil spring to check rail-to-trunnion & rcvr alignment, and then chambering tests. Both of mine took some work before everything would cycle/lock/unlock easily, with the close-tolerance gas tube

It chambered on the first attempt - sure didn't expect that! Got that same light-headed feeling again

No ejector rail made yet - hopefully tomorrow

Camera LCD is broke or it would be more centered

If you're using a standard diameter piston, here is a handy way to de-burr the inside 'step' in your custom gas tube, with a power drill
Gas tube is MUCH tighter seal (mallet fit) than a factory AK tube; had to drill out the back, so the BC snout could slide forward. That creates a smaller diameter 'step' deep inside the tube, and a problem when reassembling. Like threading a needle dozens of times, during the build. You MG47 builders will soon find out what I mean. Smoothing out that step was the key to easy reassembly

Position the front exactly where it is on a regular AK, in relation the to RSB & trunnion. Cartridge is 2.2" long. Don't go back any further than that, for starters, until you begin test feeding & ejecting. Then study how/what path the ejector pushes the casing

Had to enlarge the port higher than what's in the pic above - symetrical to the bottom, so they'd exit

Came up with an idea to eliminate the short-stroke lost pressure worries. Shorten the BC snout, then use a standard-length piston to keep the gas pressure sealed, for a longer sealed stroke. AZ Honkey suggested a good shortening technique (same as an HK51/51K) removing a section of BC snout, then re-join it, to keep the original piston threads. Need to cut the cocking handle slot, and get the 'cocking plate' made too

Been on the road all week, but home now - progress pics should be along soon

Good shot of the rails. 'Bottom' rails are the top edges of the 1.5" tube. Planning a flush buttplate with guide tubes for the recoil springs

The front will get trimmed even. Barrel is 9"/ OAL 22"

Next comes the BC extension, and locating the feed stud

Burned through the hinge pin shroud so you see some patch up. Hinge pin holes get hardened

The gas tube goes through the rear sight block to keep pressure contained for a longer stroke. Same set-up as my 6 inch shorty, but longer (4.5" stroke) to cycle the belt feed mech. AMD65 piston in a bobbed carrier, to keep the tube ID small / sealed. Will get pics of it later

Got alot of welding to do yet - some will be repair work No guarantee this will work, but hoping to be the first on my block with a 7.62x39 beltfed pistol

Steve
How are you going to mount your feed cam roller? Is it going to be like you did on your MG47 and does it have to be right on center on a RPD cover? It appears that the the cam does not track quite on the center line of the top cover.